Consumers with smartphones may quickly find it replacing their card when it comes to getting cash.

Royal Bank of Scotland ( RBS) and NatWest just introduced a mobile banking application in the U.K. that allows users to access cash at an ATM without a debit card. All a consumer has to do is request the transaction from their phone, input a six-digit transaction number provided by the bank at the ATM and scoop up their cash.

Consumers with smartphones may quickly find it replacing their card when it comes to getting cash.

For now, cash amounts are limited -- presumably to protect against I.D. fraud -- but users can use the cellphone app as many times they want in a day.

"We've heard countless stories from customers who've left their wallet behind, or parents who need a quick way to send money across to their children immediately," explains Ben Green, director of mobile banking at NatWest and RBS.

Back in the U.S., Duluth, Ga.-based NCR ( NCR) announced a similar mobile banking program this week that enables a consumer to get cash from an ATM simply by scanning their debit card at the machine. The entire transaction takes 10 seconds and "removes PINS and debit cards" from the process, NCR says of its NCR Mobile Cash Withdrawal.

Consumers may warm up to the technology. The chip embedded in the software application doesn't contain personal financial information; it just identifies the ATM location and details of the transaction. An automatic receipt is generated after the transaction and sent to the user's smartphone.

"We live in a mobile world where the modern consumer expects to handle transactions using a variety of mediums," says Michael O'Laughlin, senior vice president at NCR Financial Services. "NCR Mobile Cash Withdrawal will help financial institutions meet their customers' expectations in the mobile channel and help them deliver a differentiated and faster converged-channel experience."

The technology should also cause headaches for so-called "skimmers" -- financial fraudsters who steal debit card numbers (often as the consumer is using the card at an ATM) and use the data to steal funds from the consumer's bank account.

NCR says the technology will be fully operational by this summer. It is recruiting major banks to include the service for their consumers.